One example of semiconductor components having a breakthrough voltage are photodiodes (PD), which are semiconductor components used for converting light to an electrical current. Photodiodes are for example used in fiber optic receivers. Such a photodiode in some applications needs to be biased with a voltage that ensures high linearity and responsivity/sensitivity. If such a bias voltage is larger than the breakthrough voltage of the photodiode, a too high, possibly destructive, current may flow through the photodiode.
A specific type of photodiode is an avalanche photodiode. With such avalanche photodiodes (APDs), the bias voltage also controls the so-called avalanche gain in the diode. With common avalanche photodiodes, an optimized sensitivity is usually achieved near the breakthrough voltage, i.e. at the breakthrough voltage minus a constant offset.
Therefore, with such semiconductor components it is helpful to know the breakthrough voltage exactly to optimize the bias voltage while avoiding damage to the component.
Conventionally, the breakthrough voltage may be determined at the production of the semiconductor component using dedicated testing equipment and may for example then be stored in a look-up table. However, the breakthrough voltage may vary with temperature and aging of the component, and therefore a breakthrough voltage determined at production may not be entirely accurate later during use. Therefore, it would be desirable to be able to determine the breakthrough voltage through a (repeatable) calibration, for example in the final system. Furthermore, it would be desirable to provide an efficient way of controlling the bias voltage of such a semiconductor component such that the danger of damaging the component is at least reduced. Furthermore, in case the component is a component like a photodiode the current through which it is measured, it is desirable to provide an easy way of measuring the current and therefore to determine for example a strength of received optical power.